Improvement in steam-engine slide-valves



UNTTED STATES PATENT OEETGE.

RICHARD C. BRISTOL, OF ST. CLAIR, MICHIGAN.

IMPROVEMENT IN STEAM-ENGINE SLIDE-VALVES.

Specification forming part of' Letters Patent No. 68,980, dated October 23, ISGS.

To all `nhom it may concern:

Be it known that I, Bierman U. Buis'roL, of' St. Clair, in the county of St. Clair, in the State of- Michigan, have invented certain new and useful Improvements relative to Slide- Valves 5 and I do hereby declare that the foilowing is a full and exact description thereof'.

My improvements Yrelate to that class of valves which are carried on small rollers, arranged in two or more series, and adapted to reduce the friction by rolling backward and forward, traversing halt' the extent to which the valve travels. My present invention is intended to overcome some of the ditticulties experienced in the use of such devices, and to make the sume operate more perfectly and reliably.

I will tirst describe what I consider the best means of carrying ont my invention, and will afterward designate the points which l believe to be new.

The accompanying drawings foi-1n a part of this specification.

Figure l is a central section across the valve on the line X X in Fig. Fig. 2 is a plan view. Figli is a longitudinal section. These figures representthe valve complete in a f'orin adapted t'or use in locomotive-engines. These figures also indicate the position of the steamchest which incloses the valve, and which is relied upon to keep the rollers in position. Fig. 4 is a side view of one ofthe sets of rollers disconnected from the other parts. Fig. 5 is a plan view ot' the same. Fig. (l is a crosssection on the line Y Y in Fig. 4.

Similar letters of reference indicate correspondin g parts in all the figures. The figures represent the novel parts, with so much ofthe other parts as is necessary to indicate their relation thereto.

A is `the body of the valve. A A are bars, ot' hardened steel, ltted in the ends of the valve in the position represented, and held in place by being beveled at their ends, so as to lock or dovetail. These bars form the bearing surfaces by which the valve rests upon the series of' rollers.

B is the cylinder-face. B are bars, of hardened steel, placed as represented, so as to bear fairly on the cylindentace under each end ot' the valve A. These bars l form the lower surfaces which receive the weight of the valve through the series of' rollers.

U C, &c., are rings or hollow cylinders, ot' hardened steel, employed as rollers. They are all of uniform size, and turned so as to traverse truly and easily.

Ul C', &c., are cylindrical cross-bars, of something less diameter than the hole in C. C202 arelongitudinal bars projecting consider, ably beyond the series of' rollersG at each end, and mounted along each side of' each series ot' rollers. Each pair of bars is firmly connected by the pins U, by riveting or heading the latter therein, as indicated in the drawings, and the bars C being each made to guide a roller, U, in the manner indicated, the entire arrangement t'orms a very strong and reliable frame to guide and keep in position each roller ol' the series without allowing them to touch each other. The length of the bars U2 is so proportioned to the interior of the steam-chest and to the greatest traverse of the. valve A that the ends of the bars C'2 will nearly touch the interior of the steam-chest, first at one end Iand then at the other, as the valve reeiprocates.

The bearing-faces of the valve A are holA lowed with longitudinal grooves, as indicated by a. These grooves become tilled with steam when the valve overhangs its seat at each movement; and I find by practice that they do not interfere with the tightness ot the valve, while, I believe, th eyimaterially conduce to lightening the load on the rollers, and particularly to the rapid and easy adjustment ot' the valve-face to the diameter ot' the rollers (l, it being understood that I fit the valve itselt' so that no weight will be taken upon the rollers C in lirst fitting up a new engine or new valve, it not being necessary to scrape the valve or its seat; but, as the wearing of the valve and ot the cylinder itself ultimately lowers the valve, the rollers C commence to receive a portion of the load and soon relieve the rubbing-surface of' the valve from all abrasion, and it becomes selttting in regard to subsequent wear.

I have before received several patents for improvements in this class of valves. My present invention has been experimented with very successfully' on a numberof large steamvessels and on several severely-worked locomotives, and it has been found to greatly promote the ends in View.

In the arrangements described in my former patents the rollers were liable to rub together or turn diagonally, and thus create considerable unnecessary friction, and sometimes do great injury, as also to beeoxne huddled together toward either end of their path, and to support the vulve uuequally. My present arrangement prevents this very eeetuaiiy. I introduce the elevated projections A2 only to aid in supporting the Valve in planing' its face.

I claim- In connection with aslide-valve, the withindeseribed arrangement ot' rollers l, mounted eoneentrieally upon the erossbars C1 and between the longitudinal bars U2 U2, and arranged to operate rela-tivelyY to the valve and to the eylinderfaee and to the stemn-eliest, substantially as and for the purposes herein speeilied.

RICHARD C. BRISTOL.

vllitnesses:

l'. S. WRIGHT, E. Wmo-IIT. 

